On 2 May 2025, an Mw7.4 earthquake occurred ∼120km off the southern tip of Tierra del Fuego, at the transition of the Shackleton Fracture Zone and the Chile Trench. This event exhibits reverse‐faulting mechanisms with relatively steeply dipping planes and is the largest recorded along this complex plate boundary. Most aftershocks have similar mechanisms, although some show strike‐slip and normal faulting. To better resolve the activated fault system underl imited station coverage, were located events and incorporated pP‐sP phases identified using a trained classifier to refine focal depths. A multichannel seismic reflection line provides additional insights into the structure of the subduction complex. We infer that the mainshock nucleated on the subduction interface or within the plate of the southernmost Chilean subduction system, with aftershocks marking activation of steeper structures. This behavior emphasizes how convergent and strike‐slip fault systems interact to complicate earthquake rupture at plate boundary transitions.
The2May2025Mw7.4DrakePassageEarthquake:Insights Into Tectonics at the Shackleton Fracture Zone–Chilean Trench Transition
Vuan A.
;Brancatelli G.;Brancolini G.;Geletti R.;Lodolo E.;Magrin A.;Santulin M.;
2026-01-01
Abstract
On 2 May 2025, an Mw7.4 earthquake occurred ∼120km off the southern tip of Tierra del Fuego, at the transition of the Shackleton Fracture Zone and the Chile Trench. This event exhibits reverse‐faulting mechanisms with relatively steeply dipping planes and is the largest recorded along this complex plate boundary. Most aftershocks have similar mechanisms, although some show strike‐slip and normal faulting. To better resolve the activated fault system underl imited station coverage, were located events and incorporated pP‐sP phases identified using a trained classifier to refine focal depths. A multichannel seismic reflection line provides additional insights into the structure of the subduction complex. We infer that the mainshock nucleated on the subduction interface or within the plate of the southernmost Chilean subduction system, with aftershocks marking activation of steeper structures. This behavior emphasizes how convergent and strike‐slip fault systems interact to complicate earthquake rupture at plate boundary transitions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
