The Liquiñe-Ofqui Fault is a major right-lateral strike-slip fault stretching more than 1,000 kilometres through the Andes of southern Chile, from around Liquiñe south to the Ofqui isthmus in Patagonia. It runs parallel to the coast and lies within the overriding continental plate, above the zone where the Nazca Plate subducts beneath South America.
The fault accommodates part of the oblique convergence of the Nazca Plate: because the plate dives at an angle, a component of motion is transferred inland, sliding the coastal forearc sliver northward. Its trace closely guides the Southern Volcanic Zone, and many volcanoes sit along or near the fault where magma exploits the fractured crust.
The system generates frequent shallow earthquakes; a notable example is the 2007 Aysén sequence near Puerto Aysén, whose magnitude 6.2 mainshock triggered landslides and a fjord tsunami that killed several people. The intimate link between faulting, seismicity and volcanism makes Liquiñe-Ofqui one of the defining tectonic features of Patagonia.