Change in the pattern of crustal seismicity at the Southern Central Andes from a local seismic network

Shallow seismicity in the Southern Central Andes is associated with interplate earthquakes due to the subduction of the Nazca plate beneath the South American plate and neotectonic activity, mainly located in the retro-arc region. However, this pattern changes drastically south of 34°S within the tr...

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Autores principales:	Nacif, S., Lupari, M., Triep, E.G., Nacif, A., Álvarez, O., Folguera, A., Gímenez, M.
Formato:	JOUR
Materias:	Andean growth Crustal seismicity Erosion Fore-arc and intra-arc and back-arc Southern Central Andes Geophysics Plates (structural components) Seismology Tectonics Back-arc Central Andes Crustal earthquakes Inhomogeneous distribution Interplate earthquakes Precipitation patterns Sub-critical condition Earthquakes backarc basin earthquake event erosion forearc basin Nazca plate neotectonics seismicity subduction zone upper crust Andes Chile
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00401951_v708_n_p56_Nacif
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_00401951_v708_n_p56_Nacif
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spelling	todo:paper_00401951_v708_n_p56_Nacif2023-10-03T14:50:23Z Change in the pattern of crustal seismicity at the Southern Central Andes from a local seismic network Nacif, S. Lupari, M. Triep, E.G. Nacif, A. Álvarez, O. Folguera, A. Gímenez, M. Andean growth Crustal seismicity Erosion Fore-arc and intra-arc and back-arc Southern Central Andes Erosion Geophysics Plates (structural components) Seismology Tectonics Back-arc Central Andes Crustal earthquakes Crustal seismicity Inhomogeneous distribution Interplate earthquakes Precipitation patterns Sub-critical condition Earthquakes backarc basin earthquake event erosion forearc basin Nazca plate neotectonics seismicity subduction zone upper crust Andes Chile Shallow seismicity in the Southern Central Andes is associated with interplate earthquakes due to the subduction of the Nazca plate beneath the South American plate and neotectonic activity, mainly located in the retro-arc region. However, this pattern changes drastically south of 34°S within the transition zone at the Southern Central Andes where crustal seismicity associated with mountain-building processes concentrates at the fore-arc and intra-arc region. In order to define more accurately this transition we used data from a high density-seismic network over the Chilean fore-arc and axial Andean sector (~ 33–34.5°S). We obtained a constraint data set of 77 seismic events located mostly in the Principal Cordillera western flank in the first 10 km of the upper crust. This cluster implies an abrupt change in the pattern of seismicity at the Southern Central Andes with a set of structures in the fore-arc and intra-arc accommodating shortening. This change in the locus of crustal seismicity and particularly its location on the fore-arc and intra-arc south of 34°S is discussed on the light of different hypotheses among which changes in the precipitation pattern and erosion along the Andes were favored. Focalized erosion associated with direction of prevailing Pacific winds south of ~ 34°S could determine subcritical conditions that could be adjusted by out-of-sequence deformation causing crustal earthquakes in the fore-arc region, becoming the retro-arc zone nearly fossilized from a deformational point of view. Additionally, trench sediments associated with this change in the precipitation pattern could also favor decoupling of the subduction zone inhibiting retro-arc seismicity, although it does not explain activation of fore-arc structures south of 34°S and their absence north of this latitude. Finally, inhomogeneous distribution of seismicity through the fore-arc zone south of 34°S is discussed on the light of variable elastic thicknesses. © 2017 Elsevier B.V. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00401951_v708_n_p56_Nacif
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Andean growth Crustal seismicity Erosion Fore-arc and intra-arc and back-arc Southern Central Andes Erosion Geophysics Plates (structural components) Seismology Tectonics Back-arc Central Andes Crustal earthquakes Crustal seismicity Inhomogeneous distribution Interplate earthquakes Precipitation patterns Sub-critical condition Earthquakes backarc basin earthquake event erosion forearc basin Nazca plate neotectonics seismicity subduction zone upper crust Andes Chile
spellingShingle	Andean growth Crustal seismicity Erosion Fore-arc and intra-arc and back-arc Southern Central Andes Erosion Geophysics Plates (structural components) Seismology Tectonics Back-arc Central Andes Crustal earthquakes Crustal seismicity Inhomogeneous distribution Interplate earthquakes Precipitation patterns Sub-critical condition Earthquakes backarc basin earthquake event erosion forearc basin Nazca plate neotectonics seismicity subduction zone upper crust Andes Chile Nacif, S. Lupari, M. Triep, E.G. Nacif, A. Álvarez, O. Folguera, A. Gímenez, M. Change in the pattern of crustal seismicity at the Southern Central Andes from a local seismic network
topic_facet	Andean growth Crustal seismicity Erosion Fore-arc and intra-arc and back-arc Southern Central Andes Erosion Geophysics Plates (structural components) Seismology Tectonics Back-arc Central Andes Crustal earthquakes Crustal seismicity Inhomogeneous distribution Interplate earthquakes Precipitation patterns Sub-critical condition Earthquakes backarc basin earthquake event erosion forearc basin Nazca plate neotectonics seismicity subduction zone upper crust Andes Chile
description	Shallow seismicity in the Southern Central Andes is associated with interplate earthquakes due to the subduction of the Nazca plate beneath the South American plate and neotectonic activity, mainly located in the retro-arc region. However, this pattern changes drastically south of 34°S within the transition zone at the Southern Central Andes where crustal seismicity associated with mountain-building processes concentrates at the fore-arc and intra-arc region. In order to define more accurately this transition we used data from a high density-seismic network over the Chilean fore-arc and axial Andean sector (~ 33–34.5°S). We obtained a constraint data set of 77 seismic events located mostly in the Principal Cordillera western flank in the first 10 km of the upper crust. This cluster implies an abrupt change in the pattern of seismicity at the Southern Central Andes with a set of structures in the fore-arc and intra-arc accommodating shortening. This change in the locus of crustal seismicity and particularly its location on the fore-arc and intra-arc south of 34°S is discussed on the light of different hypotheses among which changes in the precipitation pattern and erosion along the Andes were favored. Focalized erosion associated with direction of prevailing Pacific winds south of ~ 34°S could determine subcritical conditions that could be adjusted by out-of-sequence deformation causing crustal earthquakes in the fore-arc region, becoming the retro-arc zone nearly fossilized from a deformational point of view. Additionally, trench sediments associated with this change in the precipitation pattern could also favor decoupling of the subduction zone inhibiting retro-arc seismicity, although it does not explain activation of fore-arc structures south of 34°S and their absence north of this latitude. Finally, inhomogeneous distribution of seismicity through the fore-arc zone south of 34°S is discussed on the light of variable elastic thicknesses. © 2017 Elsevier B.V.
format	JOUR
author	Nacif, S. Lupari, M. Triep, E.G. Nacif, A. Álvarez, O. Folguera, A. Gímenez, M.
author_facet	Nacif, S. Lupari, M. Triep, E.G. Nacif, A. Álvarez, O. Folguera, A. Gímenez, M.
author_sort	Nacif, S.
title	Change in the pattern of crustal seismicity at the Southern Central Andes from a local seismic network
title_short	Change in the pattern of crustal seismicity at the Southern Central Andes from a local seismic network
title_full	Change in the pattern of crustal seismicity at the Southern Central Andes from a local seismic network
title_fullStr	Change in the pattern of crustal seismicity at the Southern Central Andes from a local seismic network
title_full_unstemmed	Change in the pattern of crustal seismicity at the Southern Central Andes from a local seismic network
title_sort	change in the pattern of crustal seismicity at the southern central andes from a local seismic network
url	http://hdl.handle.net/20.500.12110/paper_00401951_v708_n_p56_Nacif
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Change in the pattern of crustal seismicity at the Southern Central Andes from a local seismic network

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