Active Faulting, Submarine Surface Rupture, and Seismic Migration Along the Liquiñe‐Ofqui Fault System, Patagonian Andes
The intra‐arc Liquiñe‐Ofqui Fault System (LOFS) is an active transpressive fault zone located in the Patagonian Andes of Chile. In 2007, a seismic sequence occurred in the Aysén Fjord region of Chilean Patagonia along the LOFS, with a Mw 6.2 main earthquake that triggered dozens of landslides, some...
Published in: | Journal of Geophysical Research: Solid Earth |
---|---|
Main Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2020
|
Subjects: | |
Online Access: | http://hdl.handle.net/2445/173665 |
id |
ftubarcepubl:oai:diposit.ub.edu:2445/173665 |
---|---|
record_format |
openpolar |
spelling |
ftubarcepubl:oai:diposit.ub.edu:2445/173665 2024-02-11T09:55:49+01:00 Active Faulting, Submarine Surface Rupture, and Seismic Migration Along the Liquiñe‐Ofqui Fault System, Patagonian Andes Villalobos, Angelo Easton, Gabriel Maksymowicz, Andrei Ruiz, Sergio Lastras Membrive, Galderic De Pascale, Gregory P. Agurto‐Detzel, Hans 2020-07-10 26 p. application/pdf http://hdl.handle.net/2445/173665 eng eng Wiley Reproducció del document publicat a: https://doi.org/10.1029/2020JB019946 Journal of Geophysical Research: Solid Earth, 2020, vol. 125, num. 9, p. e2020JB019946 Articles publicats en revistes (Dinàmica de la Terra i l'Oceà) https://doi.org/10.1029/2020JB019946 2169-9313 http://hdl.handle.net/2445/173665 706819 (c) American Geophysical Union (AGU), 2020 info:eu-repo/semantics/openAccess Terratrèmols Falles (Geologia) Paleosismologia Estratigrafia sísmica Andes Earthquakes Faults (Geology) Paleoseismology Seismic stratigraphy info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2020 ftubarcepubl https://doi.org/10.1029/2020JB019946 2024-01-24T01:14:01Z The intra‐arc Liquiñe‐Ofqui Fault System (LOFS) is an active transpressive fault zone located in the Patagonian Andes of Chile. In 2007, a seismic sequence occurred in the Aysén Fjord region of Chilean Patagonia along the LOFS, with a Mw 6.2 main earthquake that triggered dozens of landslides, some of which induced tsunami waves that caused severe damage and casualties. Through the analysis of high‐resolution seismic reflection and bathymetric data, we identify six submarine faults cutting the Late Quaternary postglacial sedimentary infill of the fjord. The most conspicuous are the dextral‐normal NE‐SW striking Quitralco fault (QF) and the N‐S striking strike‐slip Río Cuervo (RCF) and Punta Cola faults (PCF). Our paleoseismological analysis reveals at least seven paleolandslide events buried in the fjord sediments that were triggered by local paleoearthquakes, which occurred since local ice sheet retreat, that is, circa 12 kyr. By combining tectonic observations with local seismicity data, we propose a seismotectonic model for the evolution of the 2007 seismic sequence where three structures were progressively activated from the depth toward the upper continental crust, causing surface rupture along the PCF and with earthquakes, suggesting only partial ruptures along other faults. Because the other faults did not rupture to the seafloor they remain important sources of seismic hazard. Thus, the last seismic sequence was a consequence of a stress transfer from the lower‐ductile toward the upper‐brittle continental crust, close to the triple junction of the Nazca, South American, and Antarctica Plates. Our results emphasize on the potential synergies between multiple geological and geophysical methods to assess complex events. Article in Journal/Newspaper Antarc* Antarctica Ice Sheet Dipòsit Digital de la Universitat de Barcelona Patagonia Journal of Geophysical Research: Solid Earth 125 9 |
institution |
Open Polar |
collection |
Dipòsit Digital de la Universitat de Barcelona |
op_collection_id |
ftubarcepubl |
language |
English |
topic |
Terratrèmols Falles (Geologia) Paleosismologia Estratigrafia sísmica Andes Earthquakes Faults (Geology) Paleoseismology Seismic stratigraphy |
spellingShingle |
Terratrèmols Falles (Geologia) Paleosismologia Estratigrafia sísmica Andes Earthquakes Faults (Geology) Paleoseismology Seismic stratigraphy Villalobos, Angelo Easton, Gabriel Maksymowicz, Andrei Ruiz, Sergio Lastras Membrive, Galderic De Pascale, Gregory P. Agurto‐Detzel, Hans Active Faulting, Submarine Surface Rupture, and Seismic Migration Along the Liquiñe‐Ofqui Fault System, Patagonian Andes |
topic_facet |
Terratrèmols Falles (Geologia) Paleosismologia Estratigrafia sísmica Andes Earthquakes Faults (Geology) Paleoseismology Seismic stratigraphy |
description |
The intra‐arc Liquiñe‐Ofqui Fault System (LOFS) is an active transpressive fault zone located in the Patagonian Andes of Chile. In 2007, a seismic sequence occurred in the Aysén Fjord region of Chilean Patagonia along the LOFS, with a Mw 6.2 main earthquake that triggered dozens of landslides, some of which induced tsunami waves that caused severe damage and casualties. Through the analysis of high‐resolution seismic reflection and bathymetric data, we identify six submarine faults cutting the Late Quaternary postglacial sedimentary infill of the fjord. The most conspicuous are the dextral‐normal NE‐SW striking Quitralco fault (QF) and the N‐S striking strike‐slip Río Cuervo (RCF) and Punta Cola faults (PCF). Our paleoseismological analysis reveals at least seven paleolandslide events buried in the fjord sediments that were triggered by local paleoearthquakes, which occurred since local ice sheet retreat, that is, circa 12 kyr. By combining tectonic observations with local seismicity data, we propose a seismotectonic model for the evolution of the 2007 seismic sequence where three structures were progressively activated from the depth toward the upper continental crust, causing surface rupture along the PCF and with earthquakes, suggesting only partial ruptures along other faults. Because the other faults did not rupture to the seafloor they remain important sources of seismic hazard. Thus, the last seismic sequence was a consequence of a stress transfer from the lower‐ductile toward the upper‐brittle continental crust, close to the triple junction of the Nazca, South American, and Antarctica Plates. Our results emphasize on the potential synergies between multiple geological and geophysical methods to assess complex events. |
format |
Article in Journal/Newspaper |
author |
Villalobos, Angelo Easton, Gabriel Maksymowicz, Andrei Ruiz, Sergio Lastras Membrive, Galderic De Pascale, Gregory P. Agurto‐Detzel, Hans |
author_facet |
Villalobos, Angelo Easton, Gabriel Maksymowicz, Andrei Ruiz, Sergio Lastras Membrive, Galderic De Pascale, Gregory P. Agurto‐Detzel, Hans |
author_sort |
Villalobos, Angelo |
title |
Active Faulting, Submarine Surface Rupture, and Seismic Migration Along the Liquiñe‐Ofqui Fault System, Patagonian Andes |
title_short |
Active Faulting, Submarine Surface Rupture, and Seismic Migration Along the Liquiñe‐Ofqui Fault System, Patagonian Andes |
title_full |
Active Faulting, Submarine Surface Rupture, and Seismic Migration Along the Liquiñe‐Ofqui Fault System, Patagonian Andes |
title_fullStr |
Active Faulting, Submarine Surface Rupture, and Seismic Migration Along the Liquiñe‐Ofqui Fault System, Patagonian Andes |
title_full_unstemmed |
Active Faulting, Submarine Surface Rupture, and Seismic Migration Along the Liquiñe‐Ofqui Fault System, Patagonian Andes |
title_sort |
active faulting, submarine surface rupture, and seismic migration along the liquiñe‐ofqui fault system, patagonian andes |
publisher |
Wiley |
publishDate |
2020 |
url |
http://hdl.handle.net/2445/173665 |
geographic |
Patagonia |
geographic_facet |
Patagonia |
genre |
Antarc* Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctica Ice Sheet |
op_relation |
Reproducció del document publicat a: https://doi.org/10.1029/2020JB019946 Journal of Geophysical Research: Solid Earth, 2020, vol. 125, num. 9, p. e2020JB019946 Articles publicats en revistes (Dinàmica de la Terra i l'Oceà) https://doi.org/10.1029/2020JB019946 2169-9313 http://hdl.handle.net/2445/173665 706819 |
op_rights |
(c) American Geophysical Union (AGU), 2020 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1029/2020JB019946 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
125 |
container_issue |
9 |
_version_ |
1790598905944080384 |