Recent M7.6 Earthquake in Drake Passage: Tectonic Setting and Seismic History

On 10 October 2025 at 20:29 UTC, a magnitude 7.6 earthquake occurred in the Drake Passage at a focal depth of 5.6 km. This event follows the M7.5 Southern Drake Passage earthquake of 22 August 2025, located approximately 15 km away. Both shocks rank among the strongest recorded in the region since 2000. The Drake Passage lies at the boundary between the Scotia and Antarctic plates, where left-lateral transform motion along the Shackleton Fracture Zone and associated faults accommodates relative plate movement. This tectonic regime produces frequent shallow-focus earthquakes, with hypocenters commonly less than 10 km deep. The passage itself formed through seafloor spreading that began roughly 30–40 million years ago, fully opening a deep-water gateway between South America and Antarctica by the early Oligocene. Establishment of the Antarctic Circumpolar Current that followed profoundly altered global ocean circulation and contributed to the thermal isolation of Antarctica. Seismic monitoring indicates that the Scotia Plate’s eastern and western margins remain active, with historical events exceeding M7 occurring periodically. The recent pair of 2025 earthquakes aligns with this pattern of clustered moderate-to-large transform-fault ruptures. No significant tsunami was generated, consistent with the strike-slip mechanism and limited vertical seafloor displacement typical of the region. Ongoing plate motion continues to load the fault systems, underscoring the need for sustained geophysical observation in this remote but strategically important oceanic corridor.

References

USGS Earthquake Catalog Global Seismographic Network bulletins Scientific Committee on Antarctic Research tectonic summaries