Earthquake nucleation in the lower crust by local stress amplification
Deep intracontinental earthquakes are poorly understood, despite their potential to cause significant destruction. Although lower crustal strength is currently a topic of debate, dry lower continental crust may be strong under high-grade conditions. Such strength could enable earthquake slip at high...
Published in: | Nature Communications |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2020
|
Subjects: | |
Online Access: | http://hdl.handle.net/11577/3338121 https://doi.org/10.1038/s41467-020-15150-x |
id |
ftunivpadovairis:oai:www.research.unipd.it:11577/3338121 |
---|---|
record_format |
openpolar |
spelling |
ftunivpadovairis:oai:www.research.unipd.it:11577/3338121 2024-04-14T08:14:37+00:00 Earthquake nucleation in the lower crust by local stress amplification Campbell, L. R. Menegon, L. Fagereng, Å. Pennacchioni, G. Campbell, L. R. Menegon, L. Fagereng, Å. Pennacchioni, G. 2020 ELETTRONICO http://hdl.handle.net/11577/3338121 https://doi.org/10.1038/s41467-020-15150-x eng eng info:eu-repo/semantics/altIdentifier/wos/WOS:000563525400001 volume:11 issue:1 numberofpages:9 journal:NATURE COMMUNICATIONS http://hdl.handle.net/11577/3338121 doi:10.1038/s41467-020-15150-x info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85081755189 Deep intracontinental earthquakes are poorly understood, despite their potential to cause significant destruction. Although lower crustal strength is currently a topic of debate, dry lower continental crust may be strong under high-grade conditions. Such strength could enable earthquake slip at high differential stress within a predominantly viscous regime, but requires further documentation in nature. Here, we analyse geological observations of seismic structures in exhumed lower crustal rocks. A granulite facies shear zone network dissects an anorthosite intrusion in Lofoten, northern Norway, and separates relatively undeformed, microcracked blocks of anorthosite. In these blocks, pristine pseudotachylytes decorate fault sets that link adjacent or intersecting shear zones. These fossil seismogenic faults are rarely >15 m in length, yet record single-event displacements of tens of centimetres, a slip/length ratio that implies >1 GPa stress drops. These pseudotachylytes represent direct identification of earthquake nucleation as a transient consequence of ongoing, localised aseismic creep. info:eu-repo/semantics/openAccess pseudotachylytes lower crust earthquakes info:eu-repo/semantics/article 2020 ftunivpadovairis https://doi.org/10.1038/s41467-020-15150-x 2024-03-21T19:40:23Z Deep intracontinental earthquakes are poorly understood, despite their potential to cause significant destruction. Although lower crustal strength is currently a topic of debate, dry lower continental crust may be strong under high-grade conditions. Such strength could enable earthquake slip at high differential stress within a predominantly viscous regime, but requires further documentation in nature. Here, we analyse geological observations of seismic structures in exhumed lower crustal rocks. A granulite facies shear zone network dissects an anorthosite intrusion in Lofoten, northern Norway, and separates relatively undeformed, microcracked blocks of anorthosite. In these blocks, pristine pseudotachylytes decorate fault sets that link adjacent or intersecting shear zones. These fossil seismogenic faults are rarely >15 m in length, yet record single-event displacements of tens of centimetres, a slip/length ratio that implies >1 GPa stress drops. These pseudotachylytes represent direct identification of earthquake nucleation as a transient consequence of ongoing, localised aseismic creep. Article in Journal/Newspaper Lofoten Northern Norway Padua Research Archive (IRIS - Università degli Studi di Padova) Lofoten Norway Nature Communications 11 1 |
institution |
Open Polar |
collection |
Padua Research Archive (IRIS - Università degli Studi di Padova) |
op_collection_id |
ftunivpadovairis |
language |
English |
topic |
pseudotachylytes lower crust earthquakes |
spellingShingle |
pseudotachylytes lower crust earthquakes Campbell, L. R. Menegon, L. Fagereng, Å. Pennacchioni, G. Earthquake nucleation in the lower crust by local stress amplification |
topic_facet |
pseudotachylytes lower crust earthquakes |
description |
Deep intracontinental earthquakes are poorly understood, despite their potential to cause significant destruction. Although lower crustal strength is currently a topic of debate, dry lower continental crust may be strong under high-grade conditions. Such strength could enable earthquake slip at high differential stress within a predominantly viscous regime, but requires further documentation in nature. Here, we analyse geological observations of seismic structures in exhumed lower crustal rocks. A granulite facies shear zone network dissects an anorthosite intrusion in Lofoten, northern Norway, and separates relatively undeformed, microcracked blocks of anorthosite. In these blocks, pristine pseudotachylytes decorate fault sets that link adjacent or intersecting shear zones. These fossil seismogenic faults are rarely >15 m in length, yet record single-event displacements of tens of centimetres, a slip/length ratio that implies >1 GPa stress drops. These pseudotachylytes represent direct identification of earthquake nucleation as a transient consequence of ongoing, localised aseismic creep. |
author2 |
Campbell, L. R. Menegon, L. Fagereng, Å. Pennacchioni, G. |
format |
Article in Journal/Newspaper |
author |
Campbell, L. R. Menegon, L. Fagereng, Å. Pennacchioni, G. |
author_facet |
Campbell, L. R. Menegon, L. Fagereng, Å. Pennacchioni, G. |
author_sort |
Campbell, L. R. |
title |
Earthquake nucleation in the lower crust by local stress amplification |
title_short |
Earthquake nucleation in the lower crust by local stress amplification |
title_full |
Earthquake nucleation in the lower crust by local stress amplification |
title_fullStr |
Earthquake nucleation in the lower crust by local stress amplification |
title_full_unstemmed |
Earthquake nucleation in the lower crust by local stress amplification |
title_sort |
earthquake nucleation in the lower crust by local stress amplification |
publishDate |
2020 |
url |
http://hdl.handle.net/11577/3338121 https://doi.org/10.1038/s41467-020-15150-x |
geographic |
Lofoten Norway |
geographic_facet |
Lofoten Norway |
genre |
Lofoten Northern Norway |
genre_facet |
Lofoten Northern Norway |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000563525400001 volume:11 issue:1 numberofpages:9 journal:NATURE COMMUNICATIONS http://hdl.handle.net/11577/3338121 doi:10.1038/s41467-020-15150-x info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85081755189 Deep intracontinental earthquakes are poorly understood, despite their potential to cause significant destruction. Although lower crustal strength is currently a topic of debate, dry lower continental crust may be strong under high-grade conditions. Such strength could enable earthquake slip at high differential stress within a predominantly viscous regime, but requires further documentation in nature. Here, we analyse geological observations of seismic structures in exhumed lower crustal rocks. A granulite facies shear zone network dissects an anorthosite intrusion in Lofoten, northern Norway, and separates relatively undeformed, microcracked blocks of anorthosite. In these blocks, pristine pseudotachylytes decorate fault sets that link adjacent or intersecting shear zones. These fossil seismogenic faults are rarely >15 m in length, yet record single-event displacements of tens of centimetres, a slip/length ratio that implies >1 GPa stress drops. These pseudotachylytes represent direct identification of earthquake nucleation as a transient consequence of ongoing, localised aseismic creep. |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1038/s41467-020-15150-x |
container_title |
Nature Communications |
container_volume |
11 |
container_issue |
1 |
_version_ |
1796312821890285568 |