Outer rise seismicity related to the Maule, Chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphere

Most of the recent published geodetic models of the 2010 Maule, Chile mega-thrust earthquake (Mw=8.8) show a pronounced slip maximum of 15-20 m offshore Iloca (~35°S), indicating that co-seismic slip was largest north of the epicenter of the earthquake rupture area. A secondary slip maximum 8-10 m a...

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Autores principales:	Moscoso,Eduardo, Contreras-Reyes,Eduardo
Lenguaje:	English
Publicado:	Servicio Nacional de Geología y Minería (SERNAGEOMIN) 2012
Materias:	Nazca plate hydration Outer Rise Maule earthquake Seismic cycle
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062012000300012
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spelling	oai:scielo:S0718-710620120003000122012-11-15Outer rise seismicity related to the Maule, Chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphereMoscoso,EduardoContreras-Reyes,Eduardo Nazca plate hydration Outer Rise Maule earthquake Seismic cycle Most of the recent published geodetic models of the 2010 Maule, Chile mega-thrust earthquake (Mw=8.8) show a pronounced slip maximum of 15-20 m offshore Iloca (~35°S), indicating that co-seismic slip was largest north of the epicenter of the earthquake rupture area. A secondary slip maximum 8-10 m appears south of the epicenter west of the Arauco Peninsula. During the first weeks following the main shock and seaward of the main slip maximum, an outer rise seismic cluster of >450 events, mainly extensional, with magnitudes Mw=4-6 was formed. In contrast, the outer rise located seaward of the secondary slip maximum presents little seismicity. This observation suggests that outer rise seismicity following the Maule earthquake is strongly correlated with the heterogeneous coseismic slip distribution of the main megathrust event. In particular, the formation of the outer-rise seismic cluster in the north, which spatially correlates with the main maximum slip, is likely linked to strong extensional stresses transfered from the large slip of the subducting oceanic plate. In addition, high resolution bathymetric data reveals that bending-related faulting is more intense seaward of the main maximum slip, where well developed extensional faults strike parallel to the trench axis. Also published seismic constraints reveal reduced P-wave velocities in the uppermost mantle at the trench-outer rise region (7.5-7.8 km/s), which suggest serpentinization of the uppermost mantle. Seawater percolation up to mantle depths is likely driven by bending related-faulting at the outer rise. Water percolation into the upper mantle is expected to be more efficient during the co-seismic and early post-seismic periods of large megathrust earthquakes when intense extensional faulting of the oceanic lithosphere facilitates water infiltration seaward of the trench.info:eu-repo/semantics/openAccessServicio Nacional de Geología y Minería (SERNAGEOMIN)Andean geology v.39 n.3 20122012-09-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062012000300012en10.5027/andgeoV39n3-a12
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Nazca plate hydration Outer Rise Maule earthquake Seismic cycle
spellingShingle	Nazca plate hydration Outer Rise Maule earthquake Seismic cycle Moscoso,Eduardo Contreras-Reyes,Eduardo Outer rise seismicity related to the Maule, Chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphere
description	Most of the recent published geodetic models of the 2010 Maule, Chile mega-thrust earthquake (Mw=8.8) show a pronounced slip maximum of 15-20 m offshore Iloca (~35°S), indicating that co-seismic slip was largest north of the epicenter of the earthquake rupture area. A secondary slip maximum 8-10 m appears south of the epicenter west of the Arauco Peninsula. During the first weeks following the main shock and seaward of the main slip maximum, an outer rise seismic cluster of >450 events, mainly extensional, with magnitudes Mw=4-6 was formed. In contrast, the outer rise located seaward of the secondary slip maximum presents little seismicity. This observation suggests that outer rise seismicity following the Maule earthquake is strongly correlated with the heterogeneous coseismic slip distribution of the main megathrust event. In particular, the formation of the outer-rise seismic cluster in the north, which spatially correlates with the main maximum slip, is likely linked to strong extensional stresses transfered from the large slip of the subducting oceanic plate. In addition, high resolution bathymetric data reveals that bending-related faulting is more intense seaward of the main maximum slip, where well developed extensional faults strike parallel to the trench axis. Also published seismic constraints reveal reduced P-wave velocities in the uppermost mantle at the trench-outer rise region (7.5-7.8 km/s), which suggest serpentinization of the uppermost mantle. Seawater percolation up to mantle depths is likely driven by bending related-faulting at the outer rise. Water percolation into the upper mantle is expected to be more efficient during the co-seismic and early post-seismic periods of large megathrust earthquakes when intense extensional faulting of the oceanic lithosphere facilitates water infiltration seaward of the trench.
author	Moscoso,Eduardo Contreras-Reyes,Eduardo
author_facet	Moscoso,Eduardo Contreras-Reyes,Eduardo
author_sort	Moscoso,Eduardo
title	Outer rise seismicity related to the Maule, Chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphere
title_short	Outer rise seismicity related to the Maule, Chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphere
title_full	Outer rise seismicity related to the Maule, Chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphere
title_fullStr	Outer rise seismicity related to the Maule, Chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphere
title_full_unstemmed	Outer rise seismicity related to the Maule, Chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphere
title_sort	outer rise seismicity related to the maule, chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphere
publisher	Servicio Nacional de Geología y Minería (SERNAGEOMIN)
publishDate	2012
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-71062012000300012
work_keys_str_mv	AT moscosoeduardo outerriseseismicityrelatedtothemaulechile2010megathrustearthquakeandhydrationoftheincomingoceaniclithosphere AT contrerasreyeseduardo outerriseseismicityrelatedtothemaulechile2010megathrustearthquakeandhydrationoftheincomingoceaniclithosphere
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Outer rise seismicity related to the Maule, Chile 2010 megathrust earthquake and hydration of the incoming oceanic lithosphere

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