The earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (Musgrave Ranges, Australia and Lofoten, Norway)
<jats:p>This paper discusses the results of field-based geological investigations of exhumed rocks exposed in the Musgrave Ranges (Central Australia) and in Nusfjord (Lofoten, Norway) that preserve evidence for lower continental crustal earthquakes with focal depths of approximately 25–40 km....
Published in: | Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |
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Language: | English |
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Royal Society, The
2021
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Online Access: | http://hdl.handle.net/10026.1/18046 https://doi.org/10.1098/rsta.2019.0416 |
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ftunivplympearl:oai:pearl.plymouth.ac.uk:10026.1/18046 2024-06-09T07:47:35+00:00 The earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (Musgrave Ranges, Australia and Lofoten, Norway) Menegon, L Campbell, L Mancktelow, N Camacho, A Wex, S Papa, S Toffol, G Pennacchioni, G 2021-03-22 20190416-20190416 Print-Electronic application/pdf http://hdl.handle.net/10026.1/18046 https://doi.org/10.1098/rsta.2019.0416 en eng Royal Society, The England ISSN:1364-503X ISSN:1471-2962 E-ISSN:1471-2962 1364-503X 1471-2962 20190416 http://hdl.handle.net/10026.1/18046 doi:10.1098/rsta.2019.0416 2021-10-14 Not known lower crustal earthquakes pseudotachylytes ductile shear zones transient deformation dry lower continental crust journal-article Review 2021 ftunivplympearl https://doi.org/10.1098/rsta.2019.0416 2024-05-14T23:46:24Z <jats:p>This paper discusses the results of field-based geological investigations of exhumed rocks exposed in the Musgrave Ranges (Central Australia) and in Nusfjord (Lofoten, Norway) that preserve evidence for lower continental crustal earthquakes with focal depths of approximately 25–40 km. These studies have established that deformation of the dry lower continental crust is characterized by a cyclic interplay between viscous creep (mylonitization) and brittle, seismic slip associated with the formation of pseudotachylytes (a solidified melt produced during seismic slip along a fault in silicate rocks). Seismic slip triggers rheological weakening and a transition to viscous creep, which may be already active during the immediate post-seismic deformation along faults initially characterized by frictional melting and wall-rock damage. The cyclical interplay between seismic slip and viscous creep implies transient oscillations in stress and strain rate, which are preserved in the shear zone microstructure. In both localities, the spatial distribution of pseudotachylytes is consistent with a local (deep) source for the transient high stresses required to generate earthquakes in the lower crust. This deep source is the result of localized stress amplification in dry and strong materials generated at the contacts with ductile shear zones, producing multiple generations of pseudotachylyte over geological time. This implies that both the short- and the long-term rheological evolution of the dry lower crust typical of continental interiors is controlled by earthquake cycle deformation.</jats:p> <jats:p>This article is part of a discussion meeting issue ‘Understanding earthquakes using the geological record’.</jats:p> Article in Journal/Newspaper Lofoten PEARL (Plymouth Electronic Archiv & ResearchLibrary, Plymouth University) Lofoten Norway Nusfjord ENVELOPE(13.348,13.348,68.035,68.035) Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379 2193 20190416 |
institution |
Open Polar |
collection |
PEARL (Plymouth Electronic Archiv & ResearchLibrary, Plymouth University) |
op_collection_id |
ftunivplympearl |
language |
English |
topic |
lower crustal earthquakes pseudotachylytes ductile shear zones transient deformation dry lower continental crust |
spellingShingle |
lower crustal earthquakes pseudotachylytes ductile shear zones transient deformation dry lower continental crust Menegon, L Campbell, L Mancktelow, N Camacho, A Wex, S Papa, S Toffol, G Pennacchioni, G The earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (Musgrave Ranges, Australia and Lofoten, Norway) |
topic_facet |
lower crustal earthquakes pseudotachylytes ductile shear zones transient deformation dry lower continental crust |
description |
<jats:p>This paper discusses the results of field-based geological investigations of exhumed rocks exposed in the Musgrave Ranges (Central Australia) and in Nusfjord (Lofoten, Norway) that preserve evidence for lower continental crustal earthquakes with focal depths of approximately 25–40 km. These studies have established that deformation of the dry lower continental crust is characterized by a cyclic interplay between viscous creep (mylonitization) and brittle, seismic slip associated with the formation of pseudotachylytes (a solidified melt produced during seismic slip along a fault in silicate rocks). Seismic slip triggers rheological weakening and a transition to viscous creep, which may be already active during the immediate post-seismic deformation along faults initially characterized by frictional melting and wall-rock damage. The cyclical interplay between seismic slip and viscous creep implies transient oscillations in stress and strain rate, which are preserved in the shear zone microstructure. In both localities, the spatial distribution of pseudotachylytes is consistent with a local (deep) source for the transient high stresses required to generate earthquakes in the lower crust. This deep source is the result of localized stress amplification in dry and strong materials generated at the contacts with ductile shear zones, producing multiple generations of pseudotachylyte over geological time. This implies that both the short- and the long-term rheological evolution of the dry lower crust typical of continental interiors is controlled by earthquake cycle deformation.</jats:p> <jats:p>This article is part of a discussion meeting issue ‘Understanding earthquakes using the geological record’.</jats:p> |
format |
Article in Journal/Newspaper |
author |
Menegon, L Campbell, L Mancktelow, N Camacho, A Wex, S Papa, S Toffol, G Pennacchioni, G |
author_facet |
Menegon, L Campbell, L Mancktelow, N Camacho, A Wex, S Papa, S Toffol, G Pennacchioni, G |
author_sort |
Menegon, L |
title |
The earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (Musgrave Ranges, Australia and Lofoten, Norway) |
title_short |
The earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (Musgrave Ranges, Australia and Lofoten, Norway) |
title_full |
The earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (Musgrave Ranges, Australia and Lofoten, Norway) |
title_fullStr |
The earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (Musgrave Ranges, Australia and Lofoten, Norway) |
title_full_unstemmed |
The earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (Musgrave Ranges, Australia and Lofoten, Norway) |
title_sort |
earthquake cycle in the dry lower continental crust: insights from two deeply exhumed terranes (musgrave ranges, australia and lofoten, norway) |
publisher |
Royal Society, The |
publishDate |
2021 |
url |
http://hdl.handle.net/10026.1/18046 https://doi.org/10.1098/rsta.2019.0416 |
long_lat |
ENVELOPE(13.348,13.348,68.035,68.035) |
geographic |
Lofoten Norway Nusfjord |
geographic_facet |
Lofoten Norway Nusfjord |
genre |
Lofoten |
genre_facet |
Lofoten |
op_relation |
ISSN:1364-503X ISSN:1471-2962 E-ISSN:1471-2962 1364-503X 1471-2962 20190416 http://hdl.handle.net/10026.1/18046 doi:10.1098/rsta.2019.0416 |
op_rights |
2021-10-14 Not known |
op_doi |
https://doi.org/10.1098/rsta.2019.0416 |
container_title |
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |
container_volume |
379 |
container_issue |
2193 |
container_start_page |
20190416 |
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1801378791763738624 |