The Andean structure of the Sierras Pampeanas based on earthquake focal mechanisms in their Northwestern region

Modeling of broadband seismic waveforms recorded by global and Chilean networks for two moderate crustal earthquakes of the northwestern Sierras Pampeanas shows their focal mechanisms, depths and seismotectonic features. The magnitude Mw 5.8 earthquake on 28 May 2002, located in the eastern flank of...

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Autor principal: Ramos, Victor Alberto
Publicado: 2010
Materias:
Andes
Compressive deformation
Decollement levels
Earthquakes
basement rock
compression
crustal structure
decollement
deformation
earthquake epicenter
earthquake magnitude
earthquake mechanism
focal mechanism
modeling
seismic moment
seismicity
seismotectonics
strain
strike-slip fault
waveform analysis
Ambato
Argentina
Catamarca
Sierras Pampeanas
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00044822_v67_n4_p461_Alvarado
http://hdl.handle.net/20.500.12110/paper_00044822_v67_n4_p461_Alvarado
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00044822_v67_n4_p461_Alvarado
record_format dspace
spelling paper:paper_00044822_v67_n4_p461_Alvarado2023-06-08T14:26:30Z The Andean structure of the Sierras Pampeanas based on earthquake focal mechanisms in their Northwestern region Ramos, Victor Alberto Andes Compressive deformation Decollement levels Earthquakes basement rock compression crustal structure decollement deformation earthquake epicenter earthquake magnitude earthquake mechanism focal mechanism modeling seismic moment seismicity seismotectonics strain strike-slip fault waveform analysis Ambato Argentina Catamarca Sierras Pampeanas Modeling of broadband seismic waveforms recorded by global and Chilean networks for two moderate crustal earthquakes of the northwestern Sierras Pampeanas shows their focal mechanisms, depths and seismotectonic features. The magnitude Mw 5.8 earthquake on 28 May 2002, located in the eastern flank of the sierra de Velasco and the Mw 6.2 earthquake on 7 September 2004, with epicenter in the southwestern part of the sierra de Ambato, have shallow focal depths of 10 and 8 km, respectively. These results combined with the historical seismicity of the region allow us to estimate the deep structure of the Sierras Pampeanas in the study region. The seismic analyses together with interpretations of the surface structure and previous neotectonic studies ruled out extensional or strike slip deformation as the main responsible mechanism of the Present structure of this sector of the sierras de Ambato and Velasco in the northwestern Sierras Pampeanas. The comparison between the Nazca-South America plate convergence orientation as well as GPS velocities in the upper plate with the summation of the seismic moment tensor for the largest seismic energy released by crustal earthquakes of this region in the last 30 years, shows a clockwise rotation of 50° of the average P-axis orientation from the convergence orientation to the northeast suggesting important strain partition. This partition is controlled by the Eopaleozoic basement fabric, which has guided the orientation and vergence of the Andean faults. Fil:Ramos, V.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2010 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00044822_v67_n4_p461_Alvarado http://hdl.handle.net/20.500.12110/paper_00044822_v67_n4_p461_Alvarado
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Andes
Compressive deformation
Decollement levels
Earthquakes
basement rock
compression
crustal structure
decollement
deformation
earthquake epicenter
earthquake magnitude
earthquake mechanism
focal mechanism
modeling
seismic moment
seismicity
seismotectonics
strain
strike-slip fault
waveform analysis
Ambato
Argentina
Catamarca
Sierras Pampeanas
spellingShingle Andes
Compressive deformation
Decollement levels
Earthquakes
basement rock
compression
crustal structure
decollement
deformation
earthquake epicenter
earthquake magnitude
earthquake mechanism
focal mechanism
modeling
seismic moment
seismicity
seismotectonics
strain
strike-slip fault
waveform analysis
Ambato
Argentina
Catamarca
Sierras Pampeanas
Ramos, Victor Alberto
The Andean structure of the Sierras Pampeanas based on earthquake focal mechanisms in their Northwestern region
topic_facet Andes
Compressive deformation
Decollement levels
Earthquakes
basement rock
compression
crustal structure
decollement
deformation
earthquake epicenter
earthquake magnitude
earthquake mechanism
focal mechanism
modeling
seismic moment
seismicity
seismotectonics
strain
strike-slip fault
waveform analysis
Ambato
Argentina
Catamarca
Sierras Pampeanas
description Modeling of broadband seismic waveforms recorded by global and Chilean networks for two moderate crustal earthquakes of the northwestern Sierras Pampeanas shows their focal mechanisms, depths and seismotectonic features. The magnitude Mw 5.8 earthquake on 28 May 2002, located in the eastern flank of the sierra de Velasco and the Mw 6.2 earthquake on 7 September 2004, with epicenter in the southwestern part of the sierra de Ambato, have shallow focal depths of 10 and 8 km, respectively. These results combined with the historical seismicity of the region allow us to estimate the deep structure of the Sierras Pampeanas in the study region. The seismic analyses together with interpretations of the surface structure and previous neotectonic studies ruled out extensional or strike slip deformation as the main responsible mechanism of the Present structure of this sector of the sierras de Ambato and Velasco in the northwestern Sierras Pampeanas. The comparison between the Nazca-South America plate convergence orientation as well as GPS velocities in the upper plate with the summation of the seismic moment tensor for the largest seismic energy released by crustal earthquakes of this region in the last 30 years, shows a clockwise rotation of 50° of the average P-axis orientation from the convergence orientation to the northeast suggesting important strain partition. This partition is controlled by the Eopaleozoic basement fabric, which has guided the orientation and vergence of the Andean faults.
author Ramos, Victor Alberto
author_facet Ramos, Victor Alberto
author_sort Ramos, Victor Alberto
title The Andean structure of the Sierras Pampeanas based on earthquake focal mechanisms in their Northwestern region
title_short The Andean structure of the Sierras Pampeanas based on earthquake focal mechanisms in their Northwestern region
title_full The Andean structure of the Sierras Pampeanas based on earthquake focal mechanisms in their Northwestern region
title_fullStr The Andean structure of the Sierras Pampeanas based on earthquake focal mechanisms in their Northwestern region
title_full_unstemmed The Andean structure of the Sierras Pampeanas based on earthquake focal mechanisms in their Northwestern region
title_sort andean structure of the sierras pampeanas based on earthquake focal mechanisms in their northwestern region
publishDate 2010
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00044822_v67_n4_p461_Alvarado
http://hdl.handle.net/20.500.12110/paper_00044822_v67_n4_p461_Alvarado
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AT ramosvictoralberto andeanstructureofthesierraspampeanasbasedonearthquakefocalmechanismsintheirnorthwesternregion
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