The Liquiñe-Ofqui Fault is major geological fault that runs a length of roughly 1200 km in a NNE-SSW orientation and exhibits current seismicity.^[1][2] It is located in the Chilean Northern Patagonian Andes. It is a dextral intra-arc strike-slip fault.^[2] Most large stratovolcanoes of the Southern Volcanic Zone of the Andes are aligned by the fault which allows for the movement of magma and hydrothermal fluids.^[2]

The fault crosses several transverse faults including the Mocha-Villarrica Fault Zone (MVFZ) and the Biobío-Aluminé Fault Zone.^[2] The fault have had periods of ductile deformation associated to pluton emplacement be it either at great depths or by shallow intrusions.^[3]

The forces that move the fault are derivative of the oblique subduction offshore Chile's coast. This leads to partition of deformation between the subduction zone, the fore-arc and the intra-arc region where the fault lies.^[2] A portion of the fault in Aysén Region likely slipped (moved) in an aftershock a few weeks after the 1960 Valdivia earthquake.^[4] This same portion slipped again in April 2007 causing earthquakes in Aysén Fjord, triggering landslides and a local tsunami.^[4]

The fault name was coined by Francisco Hervé, I. Fuenzalida, E. Araya and A. Solano in 1979.^[5] The fault itself was first inferred by Chilean government agent Hans Steffen around 1900 who referred to it as a "tectonic furrow" (Spanish: surco tectónico).^[5]