The Liquiñe-Ofqui Fault is 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 Mw 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]
See also
editReferences
edit- ^ Lange, D.; Cembrano, J.; Rietbrock, A.; Haberland, C.; Dahm, T.; Bataille, K (April 2008). "First seismic record for intra-arc strike-slip tectonics along the Liquiñe-Ofqui fault zone at the obliquely convergent plate margin of the southern Andes". Tectonophysics. 455 (1–4): 14. Bibcode:2008Tectp.455...14L. doi:10.1016/j.tecto.2008.04.014. hdl:10533/139825.
- ^ a b c d e Pérez-Flores, Pamela; Cembrano, José; Sánchez-Alfaro, Pablo; Veloso, Eugenio; Arancibia, Gloria; Roquer, Tomás (2016). "Tectonics, magmatism and paleo-fluid distribution in a strike-slip setting: Insights from the northern termination of the Liquiñe–Ofqui fault System, Chile" (PDF). Tectonophysics. 680: 192–210. Bibcode:2016Tectp.680..192P. doi:10.1016/j.tecto.2016.05.016. Retrieved June 1, 2018.
- ^ Adriasola, Alberto C.; Stockhert, Bernhard (2008). "Cooling histories and deformation of plutonic rocks along the Liquiñe-Ofqui Fault Zone, Southern Chile (41°-42°15'S)". Revista Geológica de Chile. 35 (1): 39–61. doi:10.4067/s0716-02082008000100002.
- ^ Kanamori, Hiroo (July 2019). "Evidence for a large strike-slip component during the 1960 Chilean earthquake". Geophysical Journal International. 218 (1): 1–32. doi:10.1093/gji/ggz113. Retrieved 9 July 2022.
- ^ a b Kanamori, Hiroo; Rivera, Luis (2017). "An Mw =7.7 slow earthquake in 1960 near the Ays´en Fjord region, Chile" (PDF). Geophysical Journal International. 211: 93–106. doi:10.1093/gji/ggx292. Retrieved March 29, 2019.
- ^ a b Hauser, A. (1991). "Hans Steffen, precursor del concepto falla Liquiñe-Ofqui". Revista Geológica de Chile (in Spanish). 18: 177–179.
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