Tectonic Summary
The October 10, 2025, magnitude 7.6 earthquake, located within the Drake Passage between the southern tip of South America and the Antarctic Peninsula, occurred as the result of strike-slip faulting at shallow depth. The focal mechanism solution indicates the earthquake occurred either as left-lateral strike-slip motion on a fault striking to the west-northwest or as right-lateral strike-slip on a fault striking south. The earthquake occurred within the Antarctic plate, southwest of its boundary with the Scotia plate.
The October 10, 2025, earthquake occurred in nearly the same location as a magnitude 7.5 earthquake that occurred on August 22, 2025.
Historically, this region has few earthquakes, with only two other earthquakes of magnitude 6 or larger within 155 miles (250 km) since 1950 - a magnitude 6 in 2009, and a magnitude 6.1 in 1964. Although rare, large intraplate earthquakes (those that occur within, instead of at the edge of a plate) do occasionally occur.
While commonly plotted as points on maps, earthquakes of this magnitude are more appropriately described as slip over a larger fault area. Strike-slip faulting events of the size of the August 22, 2025, event are typically about 140 km by 20 km (length x width).