Liquiñe-Ofqui Fault
Major geological fault in Northern Chile
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The Liquiñe-Ofqui Fault is a major geological fault that runs a length of roughly 1,200 kilometres (750 mi) 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]
| Liquiñe-Ofqui Fault | |
|---|---|
| Falla de Liquiñe-Ofqui | |
Approximate extent of the Liquiñe-Ofqui Fault shown in red. Note that it is near parallel to the Peru-Chile Trench, the coastline, the Chilean Coast Range and the Andes | |
| Etymology | Liquiñe, Ofqui |
| Named by | Hervé et al. |
| Year defined | 1979 |
| Country |  Chile |
| Characteristics | |
| Range | Andes |
| Length | 1,200 km (750 mi) |
| Tectonics | |
| Plate | South American |
| Status | Active |
| Earthquakes | 1960 Valdivia earthquake aftershock, 2007 Aysén Fjord earthquakes |
| Type | Intra-arc strike-slip fault |
| Movement | Dextral |
| Orogeny | Andean |
| Volcanic arc/belt | Southern Volcanic Zone |
The fault crosses several transverse faults including the Mocha-Villarrica Fault Zone (MVFZ) and the Biobío-Aluminé Fault Zone.[2] The fault has 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] There is evidence that the fault broke as a moment magnitude 9.07 subevent in the 1960 Valdivia earthquake.[4] A portion of the fault in Aysén Region likely slipped (moved) in an aftershock a few weeks after the 1960 Valdivia earthquake.[5] This same portion slipped again in April 2007, causing earthquakes in Aysén Fjord, triggering landslides and a local tsunami.[5]
The fault name was coined by Francisco Hervé, I. Fuenzalida, E. Araya and A. Solano in 1979.[6] The existence of the fault was first inferred by Chilean government agent Hans Steffen around 1900, who referred to it as a "tectonic furrow" (Spanish: surco tectónico).[6]
