The 2 May 2025 Mw 7.4 Drake Passage Earthquake: Insights into Tectonics at the Shackleton Fracture Zone-Chilean Trench Intersection

On 2 May 2025, a Mw 7.4 earthquake occurred ~120 km off the southern tip of Tierra del Fuego, at the intersection of the Shackleton Fracture Zone and the Chilean Trench. This event is the largest recorded within this complex plate boundary, filling a gap between previous M>6 earthquakes. Most aftershocks exhibit compressional mechanisms with relatively steeply dipping planes, although some show strike-slip motion. To better resolve the activated fault system under limited station coverage, we relocated events and incorporated pP and pS phases identified using a trained classifier to constrain focal depths. Hypocentral depths range from ∼15 to 35 km, with the mainshock nucleating at ∼25 km. Aftershocks with predominantly reverse mechanisms cluster southeast of the mainshock along a steeply dipping structure near the Shackleton Fracture Zone. A 1997 multichannel seismic reflection profile crossing the epicentral region provides additional constraints on the possible complexity of the rupture process.